Different concentrations of Er3+ions doped TeO2-WO3-GeO2 transparent oxyfluoride glassy materials were fabricated by conventional melt quench method and analyzed through X-ray diffraction, Fourier Transform infrared, scanning electron microscope and energy dispersive X-ray, photoluminescence-excitation, visible emission and luminescence decay studies. Various physical, structural, spectroscopic and laser characteristic parameters were evaluated following the Judd-Ofelt theory. The studied glasses were capable of emitting intense green luminescence through (2H11/2,4S3/2) & RARR; 4I15/2 transitions. The emission of green luminescence was studied through down-conversion process at 377 nm excitation and up-conversion process at 980 nm excitation. The color coordinates were found to fall in the green region of chromaticity diagram and close to the European Broadcosting Union green illuminant. The evaluated branching ratio, stimulated emission cross-section, gain linewidth, figure of merit and the quantum efficiency corresponding to 4S3/2 & RARR; 4I15/2 transition suggests that the studied glasses find wide suitability to design green emitting solid state lighting devices.

Different concentrations of Ce3+-doped TeO2-WO3-GeO2-Ce2O3 (TWGCe) glasses were prepared by melt-quenching method and characterized. Different spectroscopic and luminescence properties were evaluated using room temperature absorption and emission spectra. The absence of sharp X-ray diffraction peaks and the presence of broad band from 18 degrees to 35 degrees shows the amorphous phase of studied glasses. The Fourier transform infrared absorption spectra show the presence of various vibrational bonds. The optical properties of TWGCe glasses were studied by exciting the glass samples at 323 nm ultraviolet wavelength. The quenching in luminescence is noticed at x = 0.5 mol% along with a red-shift at higher Ce3+ concentrations. The decay time was found decrease with increase of concentration of Ce3+ ions. These glasses emit intense blue luminescence with CIE coordinates (0.161, 0.018) when excited at 323 nm radiation. These glasses are favourable as blue light sources in the design of phosphor-based white LEDs.